join_cluster

A execute tool on the Proxmox MCP server.

SERVERProxmox MCP Server SOURCEgethosthewalrus/proxmox-mcp

High RISK CLASS

Category Execute

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/gethosthewalrus-proxmox-mcp/join-cluster.md

WHAT IT DOES

What join_cluster does on Proxmox MCP Server

AI agents invoke join_cluster to trigger actions in Proxmox MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.

RISK

Why join_cluster is rated High

Joining a Proxmox cluster is a significant infrastructure operation that modifies cluster membership, potentially affecting all nodes, VMs, containers, and HA configurations. Based on the tool name and server context (managing Proxmox VE infrastructure), this likely triggers an external operation that reconfigures node membership.

From the tool's definition Tool name 'join_cluster' on a Proxmox VE management server; description is empty and uninformative.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs join_cluster safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Proxmox MCP Server, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For join_cluster, this is the rule to start with:

join_cluster Rate-limited

join_cluster stays usable, but rate-capped: a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "join_cluster": {
      "limits": [
        {
          "counter": "join_cluster_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Proxmox MCP Server, apply this rule, and every join_cluster call is checked against it from then on.

FAQ

Questions about join_cluster

What does the join_cluster tool do? +

join_cluster is a execute tool on the Proxmox MCP Server MCP server. It is categorised as a Execute tool in the Proxmox MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on join_cluster? +

Register the Proxmox MCP Server MCP server in PolicyLayer and add a rule for join_cluster: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Proxmox MCP Server. Nothing to install.

What risk level is join_cluster? +

join_cluster is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit join_cluster? +

Yes. Add a rate_limit block to the join_cluster rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block join_cluster completely? +

Set action: deny in the PolicyLayer policy for join_cluster. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides join_cluster? +

join_cluster is provided by the Proxmox MCP Server MCP server (gethosthewalrus/proxmox-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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